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CONTENT OF BENEFICIAL COMPOUNDS IN ENSILED REHYDRATED MAIZE

Maize grain is the most important energy feed in animal nutrition, and it can be used as a dry or ensiled grain whereas, after rehydration, even dry grain could be ensiled. Maize grain is rich in bioactive compounds from carotenoids, tocols and phenolics, and acidic conditions created during ensiling could affect their content. The aim of this research was to determine contents of these beneficial compounds in rehydrated maize grain silage after 185 days of storage. Grain of hybrids Bc 344, Bc 418b, Bc 424, Bc 525, Bc 572, Kekec and Pajdaš was harvested after physiological maturity, rehydrated to 32% moisture content and ensiled in vacuum bags at room temperature with the addition of a commercial inoculant. Contents of carotenoids (lutein, zeaxanthin, β-cryptoxanthin and β-carotene) and tocols (α-, γ- and δ-tocopherol and γ-tocotrienol) were determined using HPLC method while contents of free and bound phenolics and flavonoids were determined using the spectrophotometric method. Ensiling affected contents of beneficial compounds in rehydrated maize grain silage (P<0.001). Carotenoid content decreased from 8.5 to 28.3% and tocol content from 35.3 to 56.2% while contents of total phenolics and flavonoids increased for 26 and 38%, respectively, in comparison to fresh grain. Also, acidic conditions released a considerable amount of bound resulting in an increase o f free phenolics (66%) and flavonoids (46%). Rehydrated maize grain silages of investigated hybrids varied in contents of beneficial compounds (P<0.001). Ranges for investigated hybrids were (μg/g DM) 9.3 – 20.4 for lutein, 7.9 – 21.3 for zeaxanthin, 1.2 – 4.7 for β-cryptoxanthin, 0.6 – 1.8 for β-carotene, 2.1 – 9.5 for α-tocopherol, 23.1 – 4.8 for γ-tocopherol, 1.1 – 1.7 for δ-tocopherol, 3.0 – 4.5 for γ-tocotrienol, and 3069 – 4506 and 2421 – 3286 GAE/g DM for free and bound phenolics and 460 – 702 and 1384 – 1709 CE/g DM for free and bound flavonoids. Acidic conditions created during ensiling decrease content of carotenoids and tocols and increase content of free and total phenolics and flavonoids.

maize grain, rehydrated grain silage, carotenoids, tocols, phenolics

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